Window frame profile

[Anna Kettle]

I am planning to glaze an old diamond oak mullion window in my house and want to do it in such a way that it is as waterproof as possible and as attractive as possible which calls for a compromise

Most waterproof is one sheet of glass on the exterior of the mullions

Prettiest is glass between the mullions but I have been warned off this option by several people cos it tends to leak

So what I shall do is have several panes of glass, set into a new oak frame which is external to the mullions but as close to it as possible. The division between the panes of glass will be a shaped oak bar which lines up with a mullion, so from the outside it looks somewhat like a new mullion (luckily its at first floor level)

Cue ascii art of exploded cross section of mullion and bar ...

/\ / \ / \ / \ / \

[Ian Stirling]

I assume removing the existing mullions, halving them, and fitting glass in between isn't an option?

Also, with your proposed option, you might be able to perforate the outer pane, in appropriate ways, and vent it, so you can fit an inner pane without getting too much condensation, for 90% of the benefit of double glazing.

[jacob]

Difficult to say without seeing. Was it glazed originally if so why not follow the original details? If never glazed then maybe the new glazing should be entirely separate from the mullions i.e. a new frame to the outside to avoid spoiling or confusing the old details. Are the mullions close together? if so then leaded pieces in between might work - lead cames being narrow and less visible than wood - also can be trimmed to fit uneven opening. The cames could be pinned with copper nails and sealed with white lead etc. The wood would need regular application of linseed oil every summer. Could you glaze direct i.e. fit glass between woodwork, held in place with lead tags (can't remember what they are called ask a stained glass person). Gaps then sealed with white lead mastic or modern mastic to allow for diff. movement. If the old woodwork is exposed the weakest link will be the sill detail i.e. is it weathered - a.to shed water off the top surface outside and inside for condensation, b. to prevent water running back underneath bottom surface? Without seeing it I'd guess leaded glass in between would be the best option - ask a stained glass restorer. Your idea of an imposed oak frame looks like the worst option - being a complicated compromise neither one thing or the other.

cheers

Jacob

Anna Kettle wrote:

[Anna Kettle]

No I don't think the conservaiton officer would allow that

Possibly, if I can do it without the whole thing getting too bulky

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Anna Kettle]

Not glazed originally

Yes that is what I am planning to do

When oak has been covered up with plaster for 400 years like this has, there is a chemical reaction (don't ask me for details) which makes it much less resistant to weathering, so I want to avoid a design which leaves the old oak exposed on the outside

How is that different to what you suggested a couple of paragraphs ago?

Thanks for your thoughts & please keep them coming. This is a new flavour of project for me and I want to get it right first time.

Anna ~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[jacob]

How is that different to what you suggested a couple of paragraphs ago?

If it wasn't glazed before then I wouldn't try to turn it into a glazed window. It was probably closed (if at all) with wooden shutters of some sort I guess. Or could it have been a screen with woven in wattles perhaps?

I thought you meant to try and add a new window to the structure of the old - sort of vaguely incorporated. What I would do is make a new window quite independant of the mullions and standing clear. I wouldn't even use oak, just a plain small paned small sectioned window with thin glazing bars (e.g. 14mm as per many victorian windows) using painted softwood. Then the old mullions would be seen for what they are - an interesting old architectural detail, rather than than something old converted into something a bit odd - pretending to have been a glazed window when it never was.

cheers

Jacob

[Anna Kettle]

It was glazed with oiled cloth I think. The cloth is long gone but the pins and dowel which held it in place are still there

Yes I would like to do that, sitting as close to the old window as possible

I was thinking oak cos the old window is oak, but on the other hand the door underneath is painted softwood c1910, so your argument makes sense too

14mm is the sort of magic number I need to know. You don't happen to know a source of detailed window drawings perchance? I'm fresh out of Victorian windows in this house

Thanks Anna ~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Dave]

I don't have the rest of this thread, so I may be way off target here, but...

When I used to work on civil aircraft a long time ago, the way that condensation was removed from the double glazed cabin windows was to have a small hole between the panes that was connected to a tube that went to a container that had silica gel in it. The silica gel drew the water from between the panes and was changed on a regular basis for dry stuff. For a home type of use, you could put the crystals in the oven and dry them out to use again. Don't ask me where you will have to put the silica gel that is de-misting the window though ;-)

Dave